For the vegetables: In a small bowl, whisk together the seasoning, mustard, oil and salt and pepper, to taste. Toss with the vegetables and spread in a layer on the bottom of a roasting pan.
For the chicken: Season the chicken with the chicken seasoning. Place the chicken on the vegetables in the roasting pan. Roast until golden and an instant-read thermometer registers 150 degrees F when inserted in the thickest part of the thigh, 50 minutes to 1 hour.
For the glaze: While the chicken is roasting, whisk together all the ingredients for the glaze in a pot over medium-high heat. Bring to a simmer and cook until thickened slightly. Season with salt and pepper, to taste.
When the chicken is nearly cooked through, completely coat the outside with the glaze using a pastry brush. Pour any remaining glaze over the vegetables. Roast until an instant-read thermometer registers 175 degrees F when inserted in the thickest part of the thigh, an additional 15 to 20 minutes. Remove the chicken from the oven and let rest for 10 minutes before serving.